Assembly for generating aerosol

ABSTRACT

An arrangement for generating an aerosol comprises a vaporiser chamber, a mouthpiece comprising an outlet for the aerosol, and a mixing chamber comprising an air inlet, wherein: an electric heating element for vaporising a liquid to be vaporised is arranged in the vaporiser chamber, wherein the electric heating element is in contact with a wick material configured to supply the liquid to the electric heating element; the vaporiser chamber comprises at least one nozzle arranged in a wall such that a connection is formed by the nozzle between the vaporiser chamber and the mixing chamber such that a liquid in the vaporiser chamber can enter the mixing chamber as a free jet of vapour; and the free jet of vapour is mixed in the mixing chamber with an incoming air flow entering via the air inlet to generate the aerosol, and the aerosol can exit the arrangement via the outlet.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Stage of PCT/EP2021/075326 filed on Sep. 15, 2021, which claims priority to German Patent Application 102020125538.1 filed on Sep. 30, 2020, the entire content of both are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The invention relates to an arrangement for generating aerosol, a cartridge for a vaporiser system comprising a corresponding arrangement, a vaporiser system comprising such a cartridge and a method for generating aerosol.

The subject matter of the invention is defined as disclosed herein.

It is well-known that administering active ingredients via the respiratory tract is an efficient and gentle method of supplying the human or animal body with physiologically active ingredients, traditional inhalation methods in particular, which can be carried out with sometimes the simplest means, having found a firm place both in conventional medicine and among home remedies. In these simple methods, an active ingredient dissolved in a carrier substance, frequently water, is usually heated in a pot or comparable vessel and thereby caused to vaporise.

BACKGROUND OF THE INVENTION

Due to the increasingly critical assessment of smoking in many parts of the world, i.e. the consumption of tobacco products by burning them and inhaling the resulting smoke, for example in the form of cigarettes or cigars, the focus of interest in recent years has increasingly been on inhalation methods in which the physiologically active ingredients that are traditionally absorbed via tobacco smoke are instead applied via corresponding inhalation methods that do not involve burning tobacco, this concept also being applied to other active ingredients that are otherwise frequently associated with smoking, such as tetrahydrocannabinol (THC) and other cannabinoids.

Progressive technical development has made it possible to design ever smaller corresponding vaporiser systems for vaporising a composition containing active ingredients so that today vaporiser systems are available with which vaporising a composition containing active ingredients can take place in a portable hand-held device which, for example, can be the size of a traditional cigar or a packet of cigarettes. The most prominent uses for corresponding vaporiser systems are electronic cigarettes and inhalers for medical applications.

The systems known today are mostly based on the fact that a composition stored in a reservoir, which is regularly referred to as a liquid, is vaporised by a more or less controlled supply of thermal energy from a heating element, e.g. a coiled heating filament, so that the user can inhale the resulting vapours. The liquid from the reservoir to the heating element is often supplied by a wick, so that reference is frequently made to wick-coil systems. A corresponding system is disclosed, for example, in US 20140096782 A1.

SUMMARY OF THE INVENTION

Flowing together with air in the vaporiser system, the vaporised liquid forms an aerosol which contains fine droplets formed by condensation from the gas phase. Portions of the vaporised liquid usually remain in the gaseous state, although in many commercially available systems it is also possible in addition for larger droplets to be contained in the aerosol which are ejected from the liquid phase during boiling.

A great challenge with vaporiser systems, which are intended to replace conventional cigarettes, is to create a smoking experience for the user that is comparable to conventional cigarette products so that the smoking experience is comparable to that of a conventional cigarette when the user uses the vaporiser system. On the other hand, when using corresponding vaporiser systems in the medical field, the focus is on ensuring that the active substance contained can be applied precisely to a designated region of the respiratory tract. In both cases, it must ideally be possible to implement these specifications consistently over a large number of uses.

The inventors have investigated these aspects, i.e. that of the optimum smoking experience or the targeted application of medical active substances in the respiratory tract, in extensive test series. According to the inventors, both effects are probably determined to a large extent by the size of the droplets generated in the aerosol and, in particular, their droplet size distribution. Thus, droplets ranging in diameter from approx. 1 to 5 μm are preferably deposited in the lower respiratory tract, whereas droplets above 8 μm largely remain in the upper respiratory tract. On the other hand, very fine drops are partially exhaled again by the user.

According to the inventors' findings, the depth to which the droplets generated penetrate into the respiratory tract is relevant to the question of whether it is possible to achieve a smoking experience similar to the traditional smoking product with a vaporiser system. In the course of their own investigations, the inventors realised that in order to provide vaporiser systems that enable an optimum consumption experience or medical inhalers that enable optimum application of the active substances they contain, it is important to achieve an aerosol quality that is as consistent and reproducible as possible which should ideally be characterised by a droplet size distribution that can be selectively adjusted. In this respect, it was discovered that conventional vaporiser systems known in prior art, in particular wick-coil systems, regularly fail to meet these requirements.

The overriding object of the present invention was to specify an arrangement for generating aerosol which eliminates or at least diminishes the disadvantages of the prior art.

It was a special object of the present invention to specify an arrangement for generating aerosol which can produce an aerosol with a particularly high quality. One of the requirements in this case was that the arrangement for generating aerosol should be able to produce the aerosol with as consistent a quality as possible, even over a large number of uses.

It was also an object of the present invention that the arrangement for generating aerosol can produce an aerosol whose middle-sized droplet size can be selectively adjusted and whose droplet size distribution is as narrow as possible. Here, a supplementary object was that the arrangement for generating aerosol should be able to provide an aerosol which has a particularly small middle-sized droplet size, thereby enabling the aerosol to penetrate deeply into the respiratory tract.

An additional object of the invention was furthermore to specify an arrangement for generating aerosol in which the unwanted entrainment of larger, unvaporised droplets from the liquid to be vaporised is reliably prevented.

Ideally, it should be possible to implement the objects specified above with comparatively minor modifications to conventional vaporiser systems. In addition, the arrangement for generating aerosol should advantageously be at least as powerful as the vaporiser systems known in prior art in terms of the quantity of aerosol produced, i.e. the aerosol yield achievable from the mouthpiece for every millilitre of liquid vaporised.

The inventors have realised that it is possible to achieve the objects described above by controlled guidance of the fluid flows occurring inside the vaporiser system. In the arrangements known in prior art, the air flow required for aerosol generation is usually guided directly over the surface of the heated and vaporised liquid, for example by flowing directly around a wick-coil structure. In this case, there is not only the danger that unintentionally larger, unvaporised droplets of the liquid will be entrained but also, according to the inventors' findings, sharply fluctuating mixing ratios between vapour and air can occur locally over the surface of the boiling liquid which get in the way of controlled aerosol formation, in particular controlled aerosol formation with a narrow droplet size distribution. In these setups, the possibilities of exerting a selective influence on the droplet size or the droplet size distribution in particular are regularly remote, particularly since the fluid flows inside these vaporiser systems can vary substantially due to different sucking behaviour of the users.

Surprisingly, it has now been found that the controlled fluid guidance required to achieve the objects referred to above can be implemented if the vapour produced from a liquid to be vaporised by an electric heating element does not enter a mixing chamber, in which mixing with an air flow takes place, in an uncontrolled manner but rather an arrangement for generating aerosol is provided in which the vapour arising is controlled, i.e. is guided into the mixing chamber as a free jet of vapour. This is implemented in that a vaporiser chamber is provided from which the free jet of vapour can escape through a nozzle arranged in the wall of the vaporiser chamber, through which nozzle the vapour is driven due to its own vapour pressure in the vaporiser chamber. This arrangement makes it possible to achieve a controlled mixing of air and vapour in the mixing chamber which is as uniform as possible and with which high stability and reproducibility of the aerosol properties is achieved.

An appropriate arrangement allows aerosol formation in the mixing chamber to take place at the greatest possible distance from the wall regions, thus reducing loss of aerosol due to unwanted condensation. With an appropriate arrangement for generating aerosol, it is also possible to achieve particularly small middle-sized droplet sizes and particularly advantageously narrow droplet size distributions.

Without wanting to be bound by this theory, the inventors assume that the number of initial droplets formed by homogeneous nucleation, which can serve as nuclei for further condensation, depends on the rate of change over time of the air mass fraction when a critical air mass fraction is reached in the flow. The critical air mass fraction depends in this case on the substance vaporised and the temperatures of the fluids mixed together.

It is probably the case that, at least in the size range that is probably relevant in practice, a rate of change as high as possible which is experienced by a small volume moved along in the flow when the critical situation is reached results in a larger number of droplets formed, although it cannot be ruled out that an extremely high rate of change may result in the critical range being passed through too quickly which could have an adverse effect on the number of nuclei. This large number of droplets formed by homogeneous nucleation results in a small middle-sized droplet size and a narrow droplet size distribution. Thus the inventors realised that it is necessary to achieve the fastest possible mixing of air and vapour if the goal is a small middle-sized droplet size and a narrow droplet size distribution.

In the course of development, the inventors succeeded in implementing precisely these conditions described above of controlled and rapid mixing of the fluids to produce a high rate of change over time of the air mass fraction by using a free jet of vapour. In this case, it proved to be particularly advantageous, by comparison with prior art, that using a free jet of vapour made it possible to reduce local fluctuations in the vapour concentration which, in the vaporiser systems known in prior art, unfavourably increase the distribution width of the particle sizes.

In fact, using a free jet of vapour, especially in the laminar flow region of the free jet of vapour, makes it possible to achieve particularly controlled and constant conditions in which the mixing of vapour and air depends mainly on the diffusion rate of the stratified flows which is particularly easy to control when designing a vaporiser system. In addition, by comparison with prior art, particularly high-frequency and small-scale turbulences arise in the turbulent region of the free jet of vapour which likewise facilitate particularly fast and low-fluctuation mixing with the surrounding air and thus efficient aerosol generation.

In light of these remarks, the person skilled in the art will realise that the objects referred to previously are achieved by arrangements, cartridges, vaporiser systems and methods as disclosed herein. Preferred embodiments according to the invention emerge as disclosed herein and the following statements.

Such features of cartridges, vaporiser systems and methods according to the invention, which are subsequently referred to as preferred, are combined in particularly preferred embodiments with other features referred to as preferred. Thus combinations of two or more of the objects subsequently referred to as particularly preferred are most preferred.

Preferred features of corresponding cartridges, vaporiser systems and methods emerge from the features of preferred arrangements according to the invention.

The invention relates to an arrangement for generating aerosol, comprising a vaporiser chamber, a mouthpiece with an outlet for aerosol and a mixing chamber with an air inlet,

an electric heating element for vaporising a liquid being arranged in the vaporiser chamber, said electric heating element being in contact with a wick material, i.e. a porous material with capillary effect, that is configured to supply the liquid to be vaporised to the electric heating element,

the vaporiser chamber comprising at least one first nozzle which is arranged in the wall of the vaporiser chamber such that a fluid-conducting connection is formed by the nozzle between the vaporiser chamber and the mixing chamber so that the liquid vaporised in the vaporiser chamber can enter the mixing chamber as a free jet of vapour,

the arrangement being designed such that the free jet of vapour is mixed in the mixing chamber with an air flow entering via the air inlet in order to generate an aerosol, and the generated aerosol can exit the arrangement via the outlet of the mouthpiece.

The arrangement according to the invention comprises a vaporiser chamber, a mouthpiece with an outlet for an aerosol and a mixing chamber with an air inlet. In the context of the present invention, the vaporiser chamber and the mixing chamber are to be understood as chambers at least partially separated from each other by design features. Unlike in prior art, where the vaporiser chamber is usually also the chamber in which the vapour produced is mixed with supplied air, the arrangement according to the invention thus comprises at least two separate chambers which are at least partially separated from each other by design features such that a fluid cannot pass from the vaporiser chamber into the mixing chamber completely unobstructed. In this case, most preferred are such arrangements according to the invention in which a vapour produced in the vaporiser chamber can enter the mixing chamber substantially exclusively via the first nozzle.

According to the invention, the mixing chamber has an air inlet. In the simplest embodiment, this air inlet can be a simple cut-out in the wall of the mixing chamber. The purpose of the air inlet is that when the arrangement according to the invention is used, i.e. when a user sucks on the mouthpiece, air from outside the arrangement can enter the mixing chamber, in this way enabling not only pressure equalisation but also providing the air required for aerosol generation as an air flow. Preferred are arrangements according to the invention, in which an air filter is arranged at the air inlet or in a supply line to the air inlet for filtering the air flow entering the mixing chamber or in which the air inlet is connected to a supplementary tank for receiving clean air, the supplementary tank preferably being a pressure vessel.

In the arrangement according to the invention, the vaporiser chamber comprises an electric heating element. This electric heating element is used to vaporise a liquid which can be supplied via a wick material in contact with the electric heating element. The electric heating element makes it possible to convert a liquid to be vaporised to the gas phase inside the vaporiser chamber and thus to produce a vapour.

According to the invention, the vaporiser chamber comprises at least one first nozzle through which the vapour produced can enter the mixing chamber. In the context of the present invention, the term nozzle, in accordance with the understanding of a person skilled in the art, refers to a technical apparatus for influencing a fluid flow when it passes from the vaporiser chamber into the mixing chamber, by means of which the pressure of the vapour produced in the vaporiser chamber by vaporisation of the liquid is transformed into kinetic energy of the vapour. In this case, for example, the nozzle can have a constant cross-section, can taper or even have more complex shapes. From a functional point of view, the nozzle must be able to convert the pressure of steam built up inside the vaporiser chamber into kinetic energy of the vapour so that it enters the mixing chamber as a free jet of vapour.

In the context of the present invention, a free jet is a flow unrestricted by walls from a nozzle into a free space such that the vapour flowing out of the nozzle and the gas in the mixing chamber have different velocities, the gas surrounding the free jet regularly being sucked in and entrained by the free jet.

In the simplest arrangement according to the invention, the vaporiser chamber comprises only one first nozzle. However, it is a particular advantage of the arrangement according to the invention that the flow properties of the free jet of vapour can also be adapted by providing more than one first nozzle from each of which the vapour can enter the mixing chamber as a free jet of vapour. This is also particularly advantageous because, for example, by selecting nozzles of different sizes and configured differently regarding their shape, complex distributions of particle sizes can also be selectively achieved in that the particle sizes obtained with each individual free jet of vapour are overlaid. This makes it possible, for example, to simultaneously apply two different active substances in different regions of the respiratory tract.

The arrangement according to the invention is designed such that the free jet of vapour exiting the vaporiser chamber through the nozzle is mixed in the mixing chamber with an air flow entering via the air inlet, so that the temperature of the resulting mixture in the mixing chamber drops and there is very high supersaturation which results in homogeneous condensation, i.e. homogeneous nucleation, with the desired high nucleation rate.

The at least one first nozzle can either be provided as a separate component, which is fixed in the wall of the vaporiser chamber, or in simple embodiments can also be formed directly by the wall of the vaporiser chamber so that, due to its design, it forms a nozzle as an outlet opening into the mixing chamber. In this respect, an arrangement according to the invention in which the at least one first nozzle is formed by the wall of the vaporiser chamber is preferred for cost reasons.

In dedicated tests and associated simulations, it has been shown that the best results are achieved with arrangements according to the invention in which the heating element and the first nozzle are arranged on different sides of the vaporiser chamber, in particular on opposing sides. According to the inventors' findings, this makes it possible to generate a build-up of pressure inside the vaporiser chamber that is as uniform as possible, and as a result to generate a free jet of vapour that is formed as uniformly as possible, with which the best results can often be achieved during aerosol generation.

Particularly in such cases where flat electric heating elements are used, for example, flat heater chips or heatable wire mesh, the electric heating element can also be integrated into the wall of the vaporiser chamber. This means that the vaporiser chamber is bounded, at least in sections, by the electric heating element. Therefore an arrangement according to the invention is preferred in which the electric heating element is arranged in the vaporiser chamber in such a manner that the electric heating element forms part of the vaporiser chamber, preferably part of the wall of the vaporiser chamber.

Even if this is not preferred in many cases, in light of the previous remarks, it is also possible for the electric heating element not only to form part of the wall of the vaporiser chamber but also, by virtue of its geometry, to simultaneously form the first nozzle or one of the first nozzles or all of the first nozzles. For example, a flat heater chip can be configured with through cut-outs which function as nozzles through which the vapour produced below the heater chip in the contact region of the wick can enter the mixing chamber as a free jet of vapour. Thus, preferred are arrangements according to the invention, in which the at least one first nozzle is formed by a component separate from the electric heating element or by the heating element arranged in the wall of the vaporiser chamber, the at least one first nozzle being most preferably formed by a component separate from the electric heating element.

In the course of developing the invention, it was initially still assumed that, in order to achieve the objects defined above, the arrangement according to the invention would necessarily have to be designed in such a way that the air flow also enters the mixing chamber as a free jet of air. In the course of further developing the invention, however, it became apparent that this is not necessary and that the substantial feature for achieving the objects described above is the arrangement according to the invention with the corresponding first nozzle and the corresponding embodiment of the vapour flow as a free jet of vapour. Nevertheless, it has been shown that an arrangement according to the invention, in which the air flow also enters the mixing chamber as a free jet of air, can offer advantages for certain applications, particularly as the controllability of aerosol formation is further increased and the person skilled in the art receives an additional adjustment option for the fine adjustment of aerosol formation. In these tests, it was shown that the desirable high mixing rates can be implemented in particular with such second nozzles that are configured as nozzles tapering towards the mixing chamber, the flow profile generated by a flat nozzle in particular proving to be particularly efficient.

Accordingly, an arrangement according to the invention is preferred in which the air inlet comprises at least one second nozzle such that the incoming air flow can enter the mixing chamber as a free jet of air, the at least one second nozzle being preferably a nozzle tapering towards the inside of the mixing chamber and/or the at least one second nozzle being preferably a flat nozzle, preferably a flat nozzle with a rectangular cross-section, the combined cross-sectional area of all second nozzles preferably ranging from 0.5 to 10 mm², preferably 1 to 4 mm².

When the arrangement according to the invention disclosed above is used with utilisation of a first and a second nozzle, it has proven advantageous to orientate the components of the arrangement according to the invention in such a manner that the free jet of vapour and the free jet of air intersect in the mixing chamber. It was found in this case that a large range of angles is possible with regard to the angle of intersection between the central jets of the two free jets which advantageously provides a particularly high degree of design freedom. However, it has been shown that particularly good aerosol qualities with the narrowest possible droplet size distribution are achieved in particular if the angle between the free jets is selected such that they meet as orthogonally as possible.

Accordingly, a preferred arrangement according to the invention is preferred in which the air inlet and the vaporiser chamber are arranged such that the free jet of vapour and the free jet of air intersect in the mixing chamber, preferably in the region of the laminar flow such that the central jets of the free jet of vapour and the free jet of air enclose an angle ranging from 5° to 175°, preferably 30° to 150°, particularly preferably 50° to 130°, most preferably 70° to 110°, the angle preferably being substantially 90°.

As an alternative to the arrangement described above, which if anything exploits direct mixing of the two directed free jets, it has proven particularly advantageous for certain applications to use such arrangements according to the invention in which aerosol formation takes place primarily in the boundary region between the free jet of vapour and the incoming air flow, i.e. in which aerosol formation is primarily due to diffusion at the boundary layer, which advantageously also enables additional control of the aerosol formation process via the temperature of the fluids used. Thus a preferred arrangement according to the invention is preferred in which the air inlet and the vaporiser chamber are arranged such that the free jet of vapour and the incoming air flow in the mixing chamber are substantially parallel to each other, at least in sections.

For this purpose, the free jet of vapour or the first nozzle of the vaporiser chamber and the air inlet must either be arranged directly in such a manner that the air flow and the free jet of vapour inside the mixing chamber are parallel to each other, at least in sections, or one or more air guiding elements must be provided in the mixing chamber so that parallel guidance is enabled, at least in sections. In this case, it has of course proven expedient to provide appropriate air guiding elements for the air flow and not for the free jet of vapour, particularly as deflection of the free jet of vapour would also result in unwanted condensation on the air guiding elements. Thus an arrangement according to the invention is preferred in which the air inlet and the at least one first nozzle of the vaporiser chamber are arranged such that the free jet of vapour and the incoming air flow in the mixing chamber are parallel to each other, at least in sections, or whereby one or more air guiding elements are arranged in the mixing chamber such that the free jet of vapour and the incoming air flow in the mixing chamber are parallel to each other, at least in sections. In the context of the present invention, the term parallel, in accordance with the understanding of a person skilled in the art, refers to the fact that the fluid flows are substantially parallel, it being possible to consider an angle enclosed by the flows of 5° or less, preferably 2° or less, particularly preferably 1° or less, as substantially parallel.

For the preferred arrangement described above, in which the fluid flows are parallel to each another, at least in sections, two structural arrangements have proven particularly reliable. In the first variant, air inlets are provided on different, opposing sides of the first nozzle such that the air flow entering through them flanks and flows around the free jet of vapour on at least two sides, thus creating a particularly large contact region in which aerosol generation takes place in the boundary region under comparable conditions. This has proven to be more advantageous in terms of reproducibility and the particle size distribution obtained than if the air flow enters the mixing chamber from only one side and first has to flow around the free jet of vapour in order to cause aerosol formation on the side of the free jet of vapour directed away from the air inlet. In this case, different condensation conditions appear on the different sides of the free jet of vapour which inherently also result in different middle-sized droplet sizes and wider droplet size distributions.

An arrangement according to the invention in which a single air inlet is formed around the first nozzle or first nozzles such that, for example, an annular air inlet extends coaxially around the first nozzle has proven itself as an alternative embodiment to the approach described above. The corresponding arrangement generates conditions which are as uniform as possible on all sides of the free jet of vapour and has proven to be one of the arrangements in which the region of laminar flows running parallel between the incoming air flow and the free jet of vapour in the mixing chamber is so constant over particularly long distances that advantageously aerosol generation is characterised particularly powerfully by the diffusion processes at the boundary layer. Accordingly, an arrangement according to the invention is preferred in which the mixing chamber comprises at least two air inlets or a single air inlet surrounding the at least one first nozzle which are or is arranged such that the incoming air flow in the mixing chamber is parallel on two sides of the free jet of vapour to the free jet of vapour, at least in sections.

As already disclosed for the second nozzle, it has proven advantageous to configure the at least one first nozzle or all first nozzles as nozzles tapering towards the mixing chamber. Such nozzles, also known as confusers, are particularly well suited to increasing the velocity of the vapour exiting the vaporiser chamber and obtaining a free jet of vapour which is as favourable as possible for the invention. An embodiment in which the first nozzle is a flat nozzle has also proven to be most advantageous for the first nozzle. Such a flat nozzle produces a free jet of vapour with a particularly large surface area at the same volume flow rate, thus resulting in a large boundary region to the surrounding air flow in which aerosol formation due to condensation can take place particularly efficiently. According to the inventors' findings, appropriate flat nozzles yield in particular largely condensed aerosols, i.e. dense aerosols, in which the middle-sized droplet size is particularly small due to the high number of initial nuclei. The combination of both the first and the second nozzles being flat nozzles has proven to be most preferred, since the free jets obtained with a flat profile have, in the case of intersecting free jets, a comparatively small and well-defined intersecting region with regard to the volume which enables particularly controlled aerosol formation.

Accordingly, an arrangement according to the invention is preferred in which the at least one first nozzle is a nozzle tapering towards the mixing chamber, and/or in which the combined cross-sectional area of all first nozzles ranges from 0.01 to 1 mm², preferably ranges from 0.05 to 0.8 mm², particularly preferably ranges from 0.1 to 0.5 mm², most preferably ranges from 0.15 to 0.4 mm², and/or in which the at least one first nozzle is a flat nozzle, preferably a flat nozzle with a rectangular cross-section, preferably with a gap width of 0.3 mm or less, preferably 0.2 mm or less, particularly preferably 0.05 mm or less.

The inventors have realised that, in order to achieve aerosol generation that is as advantageous as possible, it is useful to provide a thermal gradient between the fluids involved that is as large as possible. This means that the temperature difference between the hot free jet of vapour and the incoming cold air flow should be as large as possible. In this respect, the inventors have observed that, particularly during continued operation of an arrangement according to the invention, for example in an electronic cigarette, operation of the electrical vaporiser unit can result in the entire arrangement heating up, due to which the air flow entering the mixing chamber is also heated before aerosol generation, thus reducing the temperature gradient. Advantageously, it has been shown that this problem can be eliminated or at least reduced in a synergistic manner with the arrangement according to the invention. Since the vaporiser chamber in the arrangement according to the invention is in any case separated from the mixing chamber or other components of the arrangement for the purposes of generating the free jet of vapour, it is possible to form the vaporiser chamber or the walls of the vaporiser chamber, completely or partially from a thermally insulating material which at least partially shields the other components of the arrangement according to the invention from the thermal energy generated by the electric heating unit. This ensures that it is possible to maintain a temperature gradient between the exiting free jet of vapour and the air flow that is as high and as constant as possible. An arrangement according to the invention is preferred in which the vaporiser chamber has walls which, at least in sections, are formed from a thermally insulating material or are coated with a thermally insulating material, the thermally insulating material preferably having a thermal conductivity of 0.5 W/(m K) or less, preferably 0.1 W/(m K) or less.

For this purpose, the person skilled in the art can select a wide range of thermally insulating materials, whereby the person skilled in the art must commit to a suitable workable solution between low thermal conductivity and good processability of the material which satisfies his requirements, the latter depending particularly on the rest of the structure of the arrangement considered by the person skilled in the art. In addition to a plurality of possible plastics, typical insulating materials such as mineral wools or aerogels, which are usually characterised by the porous structure frequently encountered in corresponding insulating materials, have proven particularly effective as insulating materials.

The inventors have further recognised that, under certain circumstances, it can be particularly advantageous to form the first nozzle or all of the first nozzles at least partially from a thermally conductive material or to coat them with a thermally conductive material. Only at first glance does this contradict the advantages disclosed above of an embodiment of the vaporiser chamber made of insulating material. In addition to unwanted heating of the air flow by the electric heating element, which the thermally insulating material is supposed to eliminate, there may be another problem in the vaporiser chamber.

Since in the arrangements according to the invention, the vapour exits from the vaporiser chamber substantially via the first nozzle or first nozzles, the inner walls of the vaporiser chamber represent condensation surfaces on which unwanted condensation of the steam can occur. In the case of this unwanted condensation, some of the vapour, which should actually escape into the mixing chamber as a free jet of vapour to contribute there to aerosol formation, precipitates as condensed liquid on the walls of the vaporiser chamber from where, in the worst case, the liquid can even reach the user as large, unvaporised droplets via the mouthpiece. This process reduces the vapour concentration and losses occur accordingly, thus reducing the efficiency of aerosol generation and the aerosol yield. Naturally, this effect occurs not only on the walls but also on the first nozzle, particularly since the vapour has to pass through a comparatively small volume at this point, which in many cases is also cooled from the rear by the incoming air flow, and can easily become a condensation surface for the vapour due to the corresponding lower temperatures. This extends to theoretical embodiments in which the portion of the vapour condensing in the first nozzle could, in continued operation, result in reducing the effective cross-section of the first nozzle and thus alter the aerosol generation behaviour of the entire arrangement according to the invention.

To solve this problem, it is expedient, as indicated above, to form the first nozzle and/or the inner sides of the vaporiser chamber from a thermally conductive material, typical metals, such as copper, aluminum and platinum or semi-metals such as silicon, having proven to be particularly suitable. In most preferred embodiments of the arrangement according to the invention, the correspondingly formed inner sides of the vaporiser chamber and/or the first nozzle can be thermally coupled to the heating element and/or to a separate heating device to ensure that, during operation of the arrangement according to the invention, these components are at such a high temperature that condensation of the vapour on these components can be prevented or at least reduced. In this connection, the first embodiment in particular has proven particularly advantageous in the inventors' own tests, i.e. when the corresponding components are carried out with the electric heating element which is present anyway and is already available for generating the vapour, since in this case the basic function of the electric heating element can be exploited in a synergistic manner to compensate for this particular feature of the arrangement according to the invention which occurs to some extent.

In light of the previous remarks, arrangements according to the invention are preferred in which the vaporiser chamber has walls which, at least in sections, are formed on the inside of the vaporiser chamber from a thermally conductive material or are coated with a thermally conductive material, the thermally conductive material preferably having a thermal conductivity of 20 W/(m K) or more, preferably 80 W/(m K) or more, and the thermally conductive material on the inside of the vaporiser chamber being thermally coupled to the electric heating element and/or being connected to a separate heating apparatus, and/or in which the first nozzle is formed from a thermally conductive material with a thermally conductivity of 20 W/(m K) or more, preferably 80 W/(m K) or more, and the first nozzle preferably being thermally coupled to the electric heating element and/or connected to a separate heating apparatus.

Particularly preferred are arrangements according to the invention in which the individual components are aligned with each other such that aerosol formation takes place inside the mixing chamber, i.e. at the greatest possible distance from the inner walls of the mixing chamber. From a fluid dynamics point of view, it has proven to be particularly advantageous if the mixing chamber tapers towards the mouthpiece so that the outlet for aerosol in the mouthpiece functions in turn as a kind of nozzle which increases the kinetic energy of the aerosol generated towards the user. Thus an arrangement according to the invention is preferred in which the mixing chamber has an irregular cross-sectional profile along the flow direction of the aerosol, the cross-section of the mixing chamber preferably decreasing towards the mouthpiece.

Even if it is possible in principle to operate the arrangement according to the invention with all possible forms of electric heating elements, for example with wick-coil arrangements, it has been clearly shown in tests by the inventors that using a plate-shaped heater chip is particularly advantageous. Such a plate-shaped heater chip permits particularly good, controlled vapour generation and thus supports the general endeavour of the arrangement according to the invention to carry out vapour and aerosol generation in as controlled a manner as possible. Furthermore, a corresponding plate-shaped heater chip can be thermally coupled particularly well with other components of the vaporiser chamber and in addition, due to its shape, can also be provided particularly easily as a component of the vaporiser chamber. In this case, the heater chip is particularly preferably arranged on the base of the vaporiser chamber, i.e. on a side opposing the first nozzle. However, a corresponding plate-shaped heater chip can also be configured such that it not only forms a portion of the wall of the vaporiser chamber but also forms the first nozzle or a plurality of first nozzles in its interior which are provided in arrangements according to the invention. Thus an arrangement according to the invention is preferred in which the electric heating element is a wire coil or a plate-shaped heater chip, preferably a plate-shaped heater chip, particularly preferably a plate-shaped heater chip made of a doped or undoped semiconductor material which is preferably traversed by a plurality of microchannels.

The arrangement according to the invention can be combined with a liquid reservoir for receiving the liquid to be vaporised, resulting in a so-called cartridge which is suitable for use in vaporiser systems, for example in electronic cigarettes. Corresponding cartridges are frequently configured as disposable parts which, together with a reusable part, form a vaporiser system.

The invention thus also relates to a cartridge for a vaporiser system comprising an arrangement according to the invention and a liquid reservoir for receiving the liquid to be vaporised.

A cartridge according to the invention is preferred, the liquid reservoir comprising one or more materials which are selected from the group consisting of glass, crystal, metal, ceramic, wood and plastic, the reservoir preferably having a further outer shell and/or the liquid reservoir preferably being equipped with an element for pressure equalisation.

A cartridge according to the invention is preferred, the liquid reservoir being formed by a bag, the bag being made entirely or partially of silicone, rubber, latex or other suitable elastic or non-elastic material, preferably a plastic. The use of bags as a liquid reservoir is particularly advantageous, as they are inexpensive to produce and regularly generate only small quantities of waste. In addition, it is advantageously not necessary to provide pressure equalisation in the liquid reservoir, as the bag will contract if necessary while the internal pressure remains constant. In addition, from a safety point of view, bags are advantageous for certain applications because they do not splinter and are therefore associated with less potential risk.

Cartridges according to the invention are preferred, comprising a liquid in the liquid reservoir, the liquid comprising at least one active substance component, at least one first carrier substance boiling higher than the active substance component and at least one second carrier substance boiling lower than the active substance component, the active substance component preferably being selected from the group consisting of nicotine, tetrahydrocannabinol, cannabidiol, substances of the corresponding substance classes and medical active substances, and the liquid preferably further comprising one or more solvents selected from the group consisting of 1,2-propanediol, glycerol and water.

The liquid referred to above has proven to be particularly advantageous in practice for providing an active substance component to a user via a corresponding aerosol by means of an arrangement according to the invention. In the context of the invention, it was recognised that particularly small droplet sizes and a particularly narrow droplet size distribution can be achieved particularly if a proportion of glycerol is used which is as high as possible. Accordingly, cartridges according to the invention are preferred, comprising a liquid in the liquid reservoir, the percent by weight of glycerol relative to the total mass of the liquid ranging from 20-80%, preferably 30 to 60%.

As explained above, in arrangements according to the invention, the free jet of vapour and the air flow supplied for aerosol generation can be selectively adjusted to obtain the desired aerosol properties and condition. In practice, the result of this can be that the fluid volume of non-condensed vapour, air and aerosol exiting the mixing chamber is not sufficient to quickly equalise the pressure difference built up in the mouth of the user due to the user sucking, particularly if a second nozzle is also used which limits the volume of air entering the mixing chamber. In this case, despite the excellent aerosol quality, the vapour experience of the user can be adversely influenced by the impression that the arrangement according to the invention offers too much resistance to sucking by the user. For this case, it has proven advantageous to provide one or more air ducts in cartridges according to the invention with which additional air can be guided past the mixing chamber to the user to compensate for the circumstance described above. Thus, a cartridge according to the invention is preferred, comprising one or more air ducts which are adapted to guide air past the mixing chamber to the mouthpiece. In this case it has proven to be particularly effective if valves are provided in the additional air ducts which only open when a predetermined pressure difference is exceeded so that, at least at the beginning of a puff, the pressure difference generated by the user substantially results in the free jet of vapour and the air flow being formed inside the mixing chamber.

The invention further relates to a vaporiser system for vaporising a liquid, preferably for use in a portable vaporising apparatus, preferably in a hand-held device, particularly preferably in an e-cigarette or an inhaler for medical purposes, comprising a cartridge according to the invention and a reusable element comprising at least one electrical energy source for operating the electric heating element, preferably a battery or a fuel cell, particularly preferably a lithium-ion battery, in particular a lithium polymer rechargeable battery, the cartridge and the reusable element being reversibly and non-destructively detachably connected or connectable to each other such that an electrical contact is formed between the electrical energy source and the electric heating element. Use for medical purposes includes in particular the application of drugs for respiratory diseases as well as painkillers.

In conclusion, the invention also relates to a method for generating aerosol, preferably configured with an arrangement according to the invention, comprising the steps:

-   -   a) vaporising a liquid in a vaporiser chamber, with an electric         heating element arranged in the vaporiser chamber,     -   b) discharging the vaporised liquid from the vaporiser chamber         into a mixing chamber through at least one first nozzle arranged         in the wall of the vaporiser chamber to generate a free jet of         vapour,     -   c) generating an aerosol in the mixing chamber by mixing the         free jet of vapour with an air flow entering the mixing chamber         via an air inlet, and     -   d) discharging the aerosol generated from the mixing chamber via         the outlet of a mouthpiece.

The method according to the invention is preferably carried out with an arrangement according to the invention or a preferred arrangement according to the invention. The method according to the invention provides that a liquid is vaporised in a vaporiser chamber by means of an electric heating element. The vapour generated is then discharged from the vaporiser chamber into a mixing chamber, the discharging taking place through a first nozzle arranged in the wall of the vaporiser chamber so that a free jet of vapour is obtained. Subsequently, an aerosol is generated in the mixing chamber by mixing the free jet of vapour with an air flow entering the mixing chamber via an air inlet. This aerosol generated in such a manner is subsequently guided out of the mixing chamber to the user via the outlet of a mouthpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will be explained and described in greater detail below with reference to the associated drawings. In this case the drawings show:

FIG. 1 a schematic illustration of a preferred embodiment of the cartridge according to the invention with an arrangement according to the invention in cross-section;

FIG. 2 a schematic detail of a preferred arrangement according to the invention in cross-section;

FIG. 3 a schematic detail of a preferred arrangement according to the invention;

FIG. 4 a a schematic detail of a preferred arrangement according to the invention in cross-section;

FIG. 4 b a schematic detail of a preferred arrangement according to the invention in a view from above;

FIG. 5 a schematic illustration of a flat nozzle;

FIG. 6 a a schematic illustration of a first relative arrangement of first and second nozzles;

FIG. 6 b a schematic illustration of a second relative arrangement of first and second nozzles; and

FIG. 6 c a schematic illustration of a third relative arrangement of first and second nozzles.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a schematic cross-sectional representation of a cartridge 42 according to the invention which comprises an arrangement 10 according to the invention. An electric heating element 24 which is configured as a plate-shaped heater chip is arranged in the vaporiser chamber 12. This electric heating element 24 is in contact with a wick material 28, by means of which the liquid 26 to be vaporised is supplied from the liquid reservoir 44 to the electric heating element 24. In the example shown in FIG. 1 , the wick material 28 is a non-woven fabric. The liquid reservoir 44 is formed of glass, the liquid, as a solvent, comprising a mixture consisting of 1,2 propanediol, glycerol and water, in which nicotine is dissolved as an active substance component. The arrangement shown in FIG. 1 is configured for a vaporisation rate of liquid of 2 mg/s which requires a heating power of approximately 3-4 W. The mixing rate of air to vapour ranges from 5:1 to 10:1 so that the air mass flow is approximately 10 to 16 mg/s and the air volume flow is approximately 8 to 16 cm³/s.

Arranged in the vaporiser chamber 12 or in the wall 32 of the vaporiser chamber 12 is a first nozzle 30 a which is formed by a fluid-conducting connection between the vaporiser chamber 12 and the mixing chamber 20. The first nozzle 30 a ensures that the vaporised liquid 26 enters the mixing chamber 20 as a free jet of vapour 34, the first nozzle 30 a being formed in the embodiment shown as first nozzle 30 a tapering towards the mixing chamber and having a round cross-section. In the mixing chamber 20, the free jet of vapour 34 is mixed with an air flow 36 entering via the air inlet 22 a so that an aerosol 18 is generated which can exit the arrangement 10 via the mouthpiece 14 or the corresponding outlet 16 of the mouthpiece 14. In FIG. 1 , the electric heating element 24 is arranged in the vaporiser chamber 12 so that it faces the first nozzle 30 a which is not configured as a separate component but is formed by the wall 32 of the vaporiser chamber 12.

In the preferred embodiment shown in FIG. 1 , the air inlet 22 a also comprises a second nozzle 38 a which is configured as a tapering nozzle having a circular cross-section. In this case, the air inlet 22 a and the vaporiser chamber 12 or the air inlet 22 a and the first nozzle 30 a are arranged with respect to each other such that the free jet of vapour 34 and the free jet of air 40 meet in the mixing chamber 20 in the region of the laminar flow at an angle which is substantially 90°.

To prevent unwanted heating of the incoming air flow 36 by the electric heating element 24, the walls 32 of the vaporiser chamber 12 in the embodiment shown are formed of plastic which performs the function of thermal insulation. The mixing chamber 20 has an irregular cross-sectional profile along the flow direction of the aerosol 18, the cross-section of the mixing chamber 20 decreasing in particular towards the mouthpiece 14. A corresponding cartridge 42, as shown schematically in FIG. 1 , can be reversibly and non-destructively detachably combined with a reusable part in which an electrical energy storage device for operating the electric heating element 24 is arranged to form a vaporiser system according to the invention.

FIG. 2 shows schematically a detail of a preferred arrangement 10 according to the invention in cross-section, in which generation of the aerosol 18 takes place in particular in the boundary region of the free jet of vapour 34 to the incoming air flow 36. To achieve generation of the aerosol 18 which is as uniform as possible, two separate air inlets 22 a, 22 b are provided on opposing sides of the first nozzle 30 a which is formed in turn by the walls 32 of the vaporiser chamber 12, so that the resulting air flow 36 surrounds the free jet of vapour 34 as uniformly as possible on both sides.

In the preferred embodiment shown in FIG. 2 , the electric heating element 24 is again configured as a plate-shaped heater chip, which is traversed by a plurality of microchannels 25 through which the liquid 26 provided by the wick material 28 and vaporised by the electric heating element 24 can pass through the electric heating element 24.

FIG. 3 visualises schematically that the first nozzle 30 a and second nozzle 38 a shown in FIG. 1 can be moved with respect to each other so that the free jet of vapour 34 and the free jet of air 40 enclose an angle which is smaller than 90°.

FIGS. 4 a and 4 b each show, in cross-section or in a view from above respectively, an alternative embodiment to the preferred arrangement according to the invention illustrated in FIG. 2 . In the cross-sectional view shown in FIG. 4 a , it can be seen that the vapour generated in the vaporiser chamber 12 enters the mixing chamber 20 as a free jet of vapour 34 and is enclosed on all sides by the air flow 36 so that the aerosol 18 is formed, in particular, at the boundary layer between the free jet of vapour 34 and the air flow 36, while it is guided through the mixing chamber 20 to the outlet 16 for the aerosol 18 which is arranged in the mouthpiece 14.

The difference from the embodiment shown in FIG. 2 is that in this case only one air inlet 22 a is provided, but it is arranged around the first nozzle 30 a such that coaxial structure emerges and the air flow 36 entering through the air inlet 22 a surrounds the free jet of vapour 34 on all sides, as is visualised in FIG. 4 b.

FIG. 5 shows schematically a flat nozzle with a rectangular cross-section which, in the context of the invention, has proven to be a particularly suitable nozzle shape, particularly if it is configured as a nozzle tapering towards the mixing chamber 20, as shown in FIG. 5 . The flat nozzle shown schematically in FIG. 5 has proven to be an advantageous embodiment for both the first nozzle 30 a and the second nozzle 38 a, since free jets with a particularly large surface area or lateral surfaces are obtained with it.

FIGS. 6 a, 6 b and 6 c show schematically possible embodiments of nozzles which can be provided in an arrangement as shown in FIG. 1 , i.e. an arrangement 10 according to the invention, in which both a free jet of vapour 34 and a free jet of air 40 are used and which intersect in the mixing chamber 20. In this case, FIG. 6 a shows a single first nozzle 30 a and a single second nozzle 38 a, each tapering towards the mixing chamber and having a circular cross-section, as is also disclosed in FIG. 1 .

In contrast, both the air inlet 22 a and the outlet 16 from the vaporiser chamber 12 in FIG. 6 b are configured to use four nozzles each. Thus, there are four first nozzles 30 a, 30 b, 30 c, 30 d and a total of four second nozzles 38 a, 38 b, 38 c, 38 d. In the example shown in FIG. 6 , the individual nozzles are each configured as nozzles with a constant and circular cross-section.

In contrast, FIG. 6C shows an embodiment in which both the first nozzle 30 a and the second nozzle 38 a are configured as a flat nozzle with a rectangular cross-section, while in the embodiment shown in FIG. 6 c , nozzles with a cross-sectional profile that is constant over the entire length are used in each case instead of the flat nozzle shown in FIG. 5 .

REFERENCE NUMERALS

-   -   10 Arrangement     -   12 Vaporiser chamber     -   14 Mouthpiece     -   16 Outlet     -   18 Aerosol     -   20 Mixing chamber     -   22 a, 22 b Air inlet     -   24 Electric heating element     -   25 Microchannels     -   26 Liquid     -   28 Wick material     -   30 a, 30 b, 30 c, 30 d First nozzle     -   32 Wall     -   34 Free jet of vapour     -   36 Air flow     -   38 a, 38 b, 38 c, 38 d Second nozzle     -   40 Free jet of air     -   42 Cartridge     -   44 Liquid reservoir 

1-14. (canceled)
 15. An arrangement for generating an aerosol, the arrangement comprising a vaporiser chamber, a mouthpiece with an outlet for the aerosol and a mixing chamber with an air inlet, wherein: an electric heating element for vaporising a liquid is arranged in the vaporiser chamber, said electric heating element being in contact with a wick material that is configured to supply the liquid to be vaporised to the electric heating element; the vaporiser chamber comprises at least one first nozzle which is arranged in a wall of the vaporiser chamber such that a fluid-conducting connection is formed by the first nozzle between the vaporiser chamber and the mixing chamber so that the liquid vaporised in the vaporiser chamber can enter the mixing chamber as a free jet of vapour; and the arrangement is designed such that the free jet of vapour is mixed in the mixing chamber with an incoming air flow entering via the air inlet in order to generate the aerosol, and the generated aerosol can exit the arrangement via the outlet of the mouthpiece.
 16. The arrangement of claim 15, wherein the air inlet comprises at least one second nozzle such that the incoming air flow can enter the mixing chamber as a free jet of air.
 17. The arrangement of claim 16, wherein the at least one second nozzle is a nozzle tapering towards the inside of the mixing chamber.
 18. The arrangement of claim 16, wherein the at least one second nozzle is a flat nozzle with a rectangular cross-section, wherein the combined cross-sectional area of the second nozzles ranges from 0.5 to 2 mm² or from preferably 0.8 to 1.4 mm².
 19. The arrangement of claim 16, wherein the air inlet and the vaporiser chamber are arranged such that the free jet of vapour and the free jet of air intersect in the mixing chamber in a region of the laminar flow such that central jets of the free jet of vapour and the free jet of air enclose an angle ranging from 5° to 175°, or from 30° to 150°, or from 50° to 130°, or from 70° to 110°, or wherein the angle is substantially 90°.
 20. The arrangement of claim 15, wherein the air inlet and the vaporiser chamber are arranged such that the free jet of vapour and the incoming air flow are substantially parallel to each other in the mixing chamber, at least in sections.
 21. The arrangement of claim 20, wherein either: the air inlet and the at least one first nozzle of the vaporiser chamber are arranged such that the free jet of vapour and the incoming air flow are substantially parallel to each other in the mixing chamber, at least in sections; or one or more air guiding elements are arranged in the mixing chamber such that the free jet of vapour and the incoming air flow are substantially parallel to each other in the mixing chamber, at least in sections.
 22. The arrangement of claim 20, wherein the mixing chamber comprises either at least two air inlets or a single air inlet surrounding the at least one first nozzle which are or is arranged such that the incoming air flow is parallel on two sides of the free jet of vapour to the free jet of vapour in the mixing chamber, at least in sections.
 23. The arrangement of claim 15, wherein: the at least one first nozzle is a nozzle tapering towards the mixing chamber; and/or the combined cross-sectional area of all first nozzles ranges from 0.01 to 1 mm², or ranges from 0.05 to 0.8 mm², or ranges from 0.1 to 0.5 mm², or ranges from 0.15 to 0.4 mm²; and/or the at least one first nozzle is a flat nozzle.
 24. The arrangement of claim 23, wherein the at least one first nozzle is the flat nozzle with a rectangular cross-section.
 25. The arrangement of claim 24, wherein the rectangular cross-section comprises a gap width of 0.3 mm or less, or of 0.2 mm or less, or of 0.05 mm or less.
 26. The arrangement of claim 15, wherein the vaporiser chamber has walls which, at least in sections, are formed from a thermally insulating material or are coated with a thermally insulating material, wherein the thermally insulating material has a thermal conductivity of 0.5 W/(m K) or less, or of 0.1 W/(m K) or less.
 27. The arrangement of claim 15, wherein: the vaporiser chamber has walls which, at least in sections, are either formed on the inside of the vaporiser chamber from a thermally conductive material or are coated with the thermally conductive material, wherein the thermally conductive material has a thermal conductivity of 20 W/(m K) or more, or of 80 W/(m K) or more, and wherein the thermally conductive material on the inside of the vaporiser chamber is thermally coupled to the electric heating element and/or is connected to a separate heating device; and/or wherein the at least one first nozzle is formed from the thermally conductive material with a thermally conductivity of 20 W/(m K) or more, or of 80 W/(m K) or more, and wherein the at least one first nozzle is thermally coupled to the electric heating element and/or is connected to a separate heating apparatus.
 28. The arrangement of claim 15, wherein the electric heating element is a wire coil or a plate-shaped heater chip.
 29. The arrangement of claim 28, wherein the electric heating element is the plate-shaped heater chip and wherein the plate-shaped heater chip is made of a doped or undoped semiconductor material
 30. The arrangement of claim 28, wherein the electric heating element comprises the plate-shaped heater chip and wherein the plate-shaped heater chip is traversed by a plurality of microchannels.
 31. A cartridge for a vaporiser system, the cartridge comprising the arrangement of claim 15 and a liquid reservoir for receiving a liquid to be vaporised.
 32. The cartridge of claim 31, comprising one or more air ducts which are adapted to guide air past the mixing chamber to the mouthpiece.
 33. A vaporiser system for vaporising a liquid, or for use in a portable vaporising apparatus, or in a hand-held device, or in an e-cigarette or an inhaler for medical purposes, the vaporiser comprising the cartridge of claim 31 and a reusable element comprising at least one electrical energy source for operating an electric heating element, wherein the cartridge and the reusable element are reversibly and non-destructively detachably connected or connectable to each other such that an electrical contact is formed between the electrical energy source and the electric heating element.
 34. A method for generating aerosol, the method executed with the arrangement of claim 15, the method comprising: vaporising a liquid in a vaporiser chamber, with an electric heating element arranged in the vaporiser chamber; discharging a vaporised liquid from the vaporiser chamber into a mixing chamber through at least one first nozzle arranged in a wall of the vaporiser chamber to generate a free jet of vapour; generating an aerosol in the mixing chamber by mixing the free jet of vapour with an air flow entering the mixing chamber via an air inlet; and discharging the aerosol generated from the mixing chamber via an outlet of a mouthpiece. 